class: inverse, middle, left background-image: url(data:image/png;base64,#laseminverse.png) background-position:5% 95% background-size: 50% ## Thigh muscle strength is not related to <br> self-reported function in the medium to long term after anterior cruciate ligament reconstruction .font70[**Michael Girdwood**, Adam Culvenor, Richard Johnston, Ben Mentiplay, Andrea Bruder, Danilo de Oliveira Silva, Tom West, Michael Hedger, Kay Crossley] .pull-left[ .font70[SMA Conference 2022] ] --- .pull-left[ ### What we know: - Thigh muscle strength (especially quadriceps) is a key target in ACL rehabilitation .font60[(Andrade, 2020)] - Better thigh muscle strength = better self-reported outcomes in the first 1-2 years post-operatively .font60[(Ageberg, 2016; Lepley, 2018)] ] .pull-right[ ### What we **don't** know: - After the rehabilitation phase is muscle strength related to .red[self-reported function?] - Is muscle strength more important for some people ? - e.g. athletic population 🏃‍ ] .pull-down[ .center[ <img src = "quads.jpeg" width = 70%> ] ] --- class: inverse, middle ## Research Question: > - What is the relationship between thigh muscle strength and self-reported outcomes at <u>over</u> 2 years post ACLR? > > - Is this relationship different in a cohort who run regularly compared to those with ongoing symptoms --- ## Methods - Participants .content-box[ .center[ .font150[n = 120] <br> .font130[ Men and women post-ACLR <br> Aged 18-50 & >2 years post surgery] ] ] .pull-left[ #### <u>Runners</u> - n = 33 - running ≥3x / week - ≥10km / week <img src = "data:image/png;base64,#traillogo.png", width = "50%" /> ] .pull-right[ #### <u>Symptomatic Cohort</u> - n = 87 - 24-36 months post ACLR - KOOS₄ <80/100 <img src = "data:image/png;base64,#superknee.png", width = "70%" /> ] --- ## Methods - Strength Assessment .pull-left[ #### Peak isometric **quadriceps** (knee extension) and **hamstring** (knee flexion) torque - Isokinetic dynamometer - Knee flexed 60° - 3 x 6s contractions, 30s rest ] .pull-right[ <img src = "biodex.jpg", width = "90%"> ] --- ## Methods - Self-reported symptoms #### <u>Knee Osteoarthritis Outcome Score - KOOS</u> All sub-scales: - Pain - Symptoms - Dailt Living - Sport & Recreation - Quality of Life - Patellofemoral - KOOS₄ - .font70[Average of Pain, Symptoms, Sport & Recreation, Quality of Life subcales] 100 = Optimal Knee Health .font60[(Roos, 2003)] --- ## Methods - Data Analysis .center[ <br> <img src = "stats.png"> ] Beta-regression models with an interaction term to measure whether relationships differed between cohorts .font60[(Smithson, 2006)]. --- ## Results - The Population | Measure | Runners (n = 33) | Symptomatic (n = 87) | |---------|--------------------|-----| |Age (years) | 32 (7) | 31 (6) | |% Female | 36% | 36% | |BMI (kg/m2) | 23.8 (2.8) | 27.9 (5.7) | |Time since surgery (yrs) | 9.2 (7.4) | 2.7 (0.3) | |KOOS₄ | 83.0 (15.9) | 65.6 (12.8) | | Quadriceps Strength (Nm) | 207.5 (54.8) | 184.2 (59.7) | | Quadriceps LSI (%) | 102.6 (20.6)| 93.1 (12.9)| | Hamstring Strength (Nm) | 97.4 (26.3) | 83.1 (29.0) | | Hamstring LSI (%) | 92.9 (16.7) | 84.3 (13.7) | - The runners had **.black[stronger]** quadriceps and hamstrings, and reported **.black[less symptoms]**. - Time since surgery <u>was not</u> related to muscle strength --- #### No meaningful relationships between .blue[thigh muscle strength] and .red[self-reported symptoms] .center[ <img src = "ameplot.png" width = 84%> .font70[Findings were consistent for both runners and symptomatic cohorts (no interaction effect)] ] --- ## Results - **.black[Example:]** KOOS₄ Subscale - **10 Nm greater** strength = **0.3% higher** KOOS₄ .font90[(95%CI -0.3 to 0.9%)] .center[ <img src = "scatter.png"> ] --- ## Discussion .pull-left[ - Our findings consistent with most existing literature >2 years post ACLR .font60[(Ericsson 2013; Flosadottir, 2016; Norte, 2018; Moller 2009) ] - Psychological factors could contribute more to longer-term outcomes .font60[(Filbay, 2021)]. <br> ] .pull-right[ <img src = "discussion.png" > ] #### Limitations - Cross-sectional study - Strength only measured in one position isometrically - Two different population groups --- class: middle ## Key Summary .content-box[ - .blue[Thigh muscle strength] <u>was not</u> associated with .red[self-reported outcomes] in people >2 years post-surgery - Strength deficits found after the first two years of recovery may be less clinically relevant for patients ] --- class: inverse, middle background-image: url(data:image/png;base64,#laseminverse.png) background-position:5% 95% background-size: 50% .pull-left[ ## Thank you! <img src = "team.png" width = 160%> ] .right[ <br> #### Questions: [m.girdwood@latrobe.edu.au](mailto:m.girdwood@latrobe.edu.au) [@m_girdwood](https://twitter.com/m_girdwood) ####Slides: <img src = "qr.png" width = 25%> ] --- --- class: inverse, middle background-image: url(data:image/png;base64,#team2.png) background-position:15% 58% background-size: 55% .pull-left[ <br> ## Thank you! ] .right[ #### Questions: .font80[ [m.girdwood@latrobe.edu.au](mailto:m.girdwood@latrobe.edu.au) [@m_girdwood](https://twitter.com/m_girdwood) ] <br> ####Slides: <img src = "qr.png" width = 25%> ] <img src = "laseminverse.png", width = 60%>